Lightweight blocks with stone-like appearance and method of manufacture

ABSTRACT

The present disclosure describes modular blocks configured to give the appearance of natural or cut stone. An aesthetic coating composition may be applied to one or more surfaces of a block having a low-density, such as an insulating concrete form (ICF), to form an modular block having the appearance of cut stone. The aesthetic coating composition includes a binder component, such as a cementitious binder made from white Portland cement, or a polymer binder such as an acrylic binder, an aggregate component, such as a limestone aggregate component, and optionally an adhesive component. The aggregate component includes a fine sand portion and a coarse sand portion that effectively enable the appearance of cut stone after finishing of the aesthetic coating surface via sanding, polishing, sandblasting, acid etching, acid finishing, or exposed aggregate finishing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/041,088, filed Jun. 18, 2020, which is incorporated by reference.

BACKGROUND

Building structures such as walls and fences are often built byorganizing several individual masonry units into the structure. Themasonry units may be pieces of cut stone, such as marble, granite,travertine, sandstone, or limestone. Frequently, masonry units are someform of brick. Bricks are typically laid together in an alternatingpattern of offset courses and joined together using mortar. Therelatively smaller bricks often seen in residential applications aretypically made of clay combined with sand or other type of aggregate andusually fired to provide suitable strength.

Concrete is also utilized to form masonry units. Masonry units formedfrom concrete are often referred to as cinder blocks, breeze blocks,hollow blocks, construction blocks, clinker blocks, and Besser blocks.The terms “concrete blocks” and “concrete masonry unit” (CMU) are oftenused to generally refer to all such varieties. Concrete blocks are madefrom cast concrete, which typically includes Portland cement and asuitable aggregate material. Lower cost concrete blocks often useindustrial wastes such as low-quality fly ash or bottom ash as at leastpart of the aggregate. This is why such blocks are commonly referred toas “cinder blocks” in the United States.

Concrete blocks are useful, low cost building units and are particularlybeneficial for forming walls of buildings. Concrete blocks can beutilized for structural and/or architectural purposes. When properlyreinforced, CMUs can support structural loads. Despite these benefits,concrete blocks are typically considered to be unsightly or too“industrial” for many residential or business environments. They aremost often used for utilitarian purposes of low esthetic value.

Furthermore, concrete blocks are a relatively heavy building material,having a density of about 2000 kg/m³ or more, requiring significant timeand labor for construction. Concrete blocks are typically rigid and candevelop cracks over time. Concrete blocks can permit significant heatloss, resulting in high energy costs for heating and cooling residentialand commercial structures.

Insulating concrete forms (ICFs) have emerged as an energy andcost-efficient alternative to cinderblocks and concrete walls.Generally, ICFs comprise a rigid insulating layer forming exteriorand/or interior wall substrates. The forms can comprise modularinterlocking units that can be stacked, reinforced, and backfilled withconcrete to form structural walls or floors of a building. Once lockedin place, the interior space between inner and outer walls of the ICFsis filled with concrete. Reinforcing steel bars (“rebar”) can be placedinside of the ICFs before concrete is poured to give the concreteincreased tensile and flexural strength.

ICFs are increasingly used to satisfy energy-efficient building codesand natural disaster resistant building codes. ICFs may also provideadditional building enhancements including soundproofing, space to runelectrical and plumbing, backing for finishes, improved indoor airquality and climate control.

However, ICFs, similar to concrete and cinderblocks, lack aestheticappeal and incur additional costs in labor and materials in order toapply aesthetic coverings. Many preferred coverings may includehigh-quality stone or brick, which can be costly and are labor-intensiveto install.

BRIEF SUMMARY

Disclosed herein are lightweight blocks configured to give theappearance of cut stone and compositions and methods of manufacturingsuch lightweight blocks. Lightweight block substrates are typically madefrom a lightweight polymer, such as molded expanded polystyrene (EPS),polyurethane, and the like, and can have any desired shape. In someembodiments, the lightweight block substrate can have a shape similar toconventional CMUs, bricks, or other building blocks. In one embodiment,the lightweight block substrate can be an insulated concrete form (ICF).Lightweight blocks can include at least one surface having or treatedwith a plaster, stucco, or other aesthetic coating compositionformulated to give the appearance of cut stone.

Lightweight block substrates typically comprise a lightweight materialhaving a density less than 1680 kg/m³, such as less than about 1500kg/m³, or less than about 1250 kg/m³, or less than about 1000 kg/m³, orless than about 750 kg/m³, or less than about 500 kg/m³, or less thanabout 300 kg/m³, or less than about 200 kg/m³, or less than about 150kg/m³, or less than about 100 kg/m³, or less than about 80 kg/m³, orless than about 60 kg/m³.

In some embodiments, the aesthetic coating composition includes a bindercomponent and an aggregate component. The binder component may include acementitious binder that includes Portland cement, such as white cementor grey cement, alone or in combination with one or more supplementarycementitious materials (SCMs), such as fly ash, metakaolin, pumice,natural pozzolan, slag, or silica fume. Alternatively, or in addition tothe cementitious binder, the binder component may comprise a polymerbinder, such as an acrylic binder that includes an acrylic resin and/orpolymer. Other polymer binders include, but are not limited to,polyvinyl alcohol (PVA), alkyd resins, polyurethane, and other materialstypically used to paint, seal or protect a wall surface.

In some embodiments, the aggregate component can be one or morelimestone aggregates, one or more silica aggregates, or a combination oflimestone and silica aggregates of same or different size. In someembodiments, at least two gradations (or sizes) of aggregates can beused, such as two differently sized limestone aggregates, twodifferently sized silica aggregates, or a combination of differentlysized limestone and silica aggregates.

In some embodiments, the aggregate component may include a fine sandportion and a coarse sand portion. The fine sand portion, which may beconsidered to be a filler and not an SCM, may have, for example, a D90within a range of about 0.075 mm to 0.425 mm, or about 0.105 mm to 0.300mm, or about 0.150 mm to 0.212 mm, and a D50 of 0.075 mm or less. Thecoarse sand portion may have, for example, a D90 within a range of about0.425 mm to 2.80 mm, or about 0.60 mm to 1.70 mm, a D50 within a rangeof about 0.212 mm to 0.60 mm, or about 0.300 mm to 0.425 mm, and a D10within a range of about 0.075 mm to 0.212 mm, or about 0.105 mm to 0.150mm.

The use of two separate gradations of aggregates improves rheology andbeneficially provides the appearance of natural or cut stone after theaesthetic coating composition has cured and finished. With respect torheology, the fine sand portion can provide workability, cohesiveness,and texture to the aesthetic coating composition. With respect toaesthetic look, exposed grains of the coarse sand portion can providethe appearance of distributed crystal facets to the finished surface ofthe coating. The resulting appearance beneficially resembles that ofnatural or cut stone.

A method of manufacturing a lightweight block includes the steps ofproviding a lightweight block substrate and applying a plaster, stucco,or other aesthetic coating composition to at least one surface of thelightweight block substrate to form an intermediate block comprising thelightweight block substrate and one or more aesthetic coating layers.The formed plaster, stucco, or other aesthetic coating layer may then beleveled by moving the intermediate block past a leveler, or vice versa,such as at least one of a leveling blade or roller. Then, the plaster,stucco, or other aesthetic coating composition layer may be allowed toharden or cure.

Following sufficient hardening or curing of the aesthetic coating layer,the aesthetic coating layer may be finished using one or more finishingprocesses to provide a desired finish. Examples include sanding,polishing, sandblasting, acid etching, acid finishing, exposed sandgrain finishing using a face retarder and power washer, and sealing. Atleast some finishing processes beneficially abrade the coarse sandportion of the aesthetic coating to form and/or expose the crystalfacets that resemble those of cut stone. A polymer or other sealant canbe applied to the finished surface to seal, waterproof, and/or protectthe aesthetic coating layer.

Also disclosed herein are systems for manufacturing lightweight blockshaving the appearance of cut stone. In one embodiment, a system formanufacturing lightweight blocks includes a conveyance system configuredto convey one or more lightweight block substrates past a series ofmodifying machines. The modifying machines include: an applicatorconfigured to apply a plaster, stucco, or other aesthetic coatingcomposition to at least one surface of the lightweight block substrateto form an intermediate aesthetic coating layer; a leveler configured toslough off or remove excess plaster, stucco, or other aesthetic coatingcomposition from an outer surface of the intermediate aesthetic coatinglayer; and one or more finishers, such as one or more of sander,polisher, sandblaster, applicator for acid etch, applicator for acidwash, applicator for face retarder, and power washer configured to alterthe surface of the plaster layer. The system may additionally includeone or more of: a holding section for allowing the intermediateaesthetic coating layer to harden or cure prior to finishing; a cleanerconfigured to remove residual debris after finishing; and a sealerconfigured to apply a sealant to the surface of the aesthetic coatinglayer.

Additional features and advantages will be set forth in part in thedescription that follows, and in part will be obvious from thedescription, or may be learned by practice of the embodiments disclosedherein. It is to be understood that both the foregoing brief summary andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the embodiments disclosed herein or asclaimed.

BRIEF DESCRIPTION OF DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features can be obtained, a more particular descriptionof various embodiments will be rendered by reference to the appendeddrawings. Understanding that these drawings depict only sampleembodiments and are not, therefore, to be considered to be limiting ofthe scope of the invention, the embodiments will be described andexplained with additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 illustrates an exemplary lightweight block including a substratesurface that has been formed or treated with a plaster, stucco, or otheraesthetic coating composition formulated for providing an aestheticsurface, such as to give the appearance of natural or cut stone;

FIGS. 2 through 4 illustrate exemplary manufacturing processes andsystems for forming a lightweight block such as shown in FIG. 1;

FIG. 5 illustrates an exemplary wall being formed by applying anaesthetic coating applied to the surface of insulated concrete form(ICF) blocks;

FIG. 6A is a perspective view of an exemplary lightweight block formedusing an ICF as the lightweight block substrate and including anaesthetic coating;

FIG. 6B illustrates a cross-sectional view of the lightweight block ofFIG. 6A;

FIGS. 7 through 9 illustrate exemplary manufacturing processes andsystems for forming a lightweight block using an ICF as the lightweightblock substrate, such as the lightweight block shown in FIGS. 6A and 6B;

FIGS. 10 through 11 illustrate exemplary manufacturing processes andsystems for forming a lightweight block having two coated surfaces usingan ICF as the lightweight block substrate;

FIGS. 12A and 12B illustrate an exemplary method of forming walls usinglightweight blocks;

FIGS. 13A and 13B illustrate another exemplary embodiment of alightweight block in which one side of an ICF block substrate comprisesa temporary form layer; and

FIG. 14 illustrates an exemplary method of forming a wall using thelightweight block of FIGS. 13A and 13B.

DETAILED DESCRIPTION

Disclosed herein are lightweight blocks configured to give theappearance of cut stone and compositions and methods of manufacturingsuch lightweight blocks. Lightweight blocks include lightweight blocksubstrate and at least one surface having or treated with a plaster,stucco, or other aesthetic coating composition formulated to give theappearance of natural or cut stone.

I. Lightweight Blocks

Lightweight blocks include lightweight insulating concrete forms orother lightweight block substrates that have been modified by applying aplaster, stucco, or other aesthetic coating composition to at least onesurface of the lightweight block substrate. The lightweight blocksubstrate comprises a lightweight material, such as lightweight foamconcrete, lightweight foam ceramic, expanded polystyrene (EPS), extrudedpolystyrene foam (XPS), polyurethane foam, cement-bonded wood fiber,cement-bonded polystyrene beads, cellular concrete, or similar materialshaving a density of less than 1680 kg/m³.

In some embodiments, the lightweight block substrate comprises alightweight material having a density less than about 1500 kg/m³, orless than about 1250 kg/m³, or less than about 1000 kg/m³, or less thanabout 750 kg/m³, or less than about 500 kg/m³, or less than about 300kg/m³, or less than about 200 kg/m³, or less than about 150 kg/m³, orless than about 100 kg/m³, or less than about 80 kg/m³, or less thanabout 60 kg/m³.

For simplicity, the following description will use the terms “substrate”or “block substrate” to refer generally to substrates (e.g., structuralor non-structural) having a surface that can be coated with a plastermaterial.

Particularly preferred embodiments utilize expanded polystyrene (EPS)foam as the lightweight block substrate material, though it will beunderstood that the embodiments described herein are not limited to EPSfoam.

The plaster, stucco, or other aesthetic coating composition isformulated to provide a beneficial aesthetic and/or structuralappearance to the treated surface of at least one side of a lightweightblock. The aesthetic coating composition may, for example, provide theappearance of natural or cut stone. The lightweight block can thereforebe utilized in architectural and/or decorative applications with lessexpense and with greater design freedom as compared to natural or cutstone.

FIG. 1 is an isometric view of an exemplary lightweight block 100including a lightweight block substrate 103 having first and secondsides 102, 104 and an aesthetic coating layer 114 on at least one side.The cuboid shape (e.g., a three-dimensional rectangular prism) oflightweight block 100 illustrated in FIG. 1 can be the same as orsimilar to typical blocks (e.g., CMU blocks) known in the art, thoughother embodiments may be shaped differently so long as they may bearranged with other blocks to form a building structure. For example,other embodiments of a lightweight block may have a cube shape, atrapezoidal prism shape, a panel/tile shape, a shape with a polygonalcross-section, or a shape with one or more curved surfaces.Additionally, or alternatively, some embodiments may include cornersand/or edges that are rounded, beveled, chamfered, and the like.

In some embodiments, only a single side of the lightweight blocksubstrate includes or is treated with a plaster, stucco, or otheraesthetic coating composition to form an aesthetic coating layer. Oncemultiple blocks have been arranged to form a building structure, theaesthetic coating layer is usually the only surface that is visible. Insome cases, grooves or recesses may be provided to receive grout, whichcan complete the finished appearance of layered stone. However, othersurfaces may also be treated according to the needs of a particularapplication. For example, corner and end pieces may have two or moreexposed surfaces following formation of the building structure. In somecases, opposing surfaces may remain visible after construction, such aswhere the lightweight blocks are used to form a partition wall thatremains visible from either side of the wall following construction. Insuch cases, both surfaces of the lightweight block substrate may betreated to have an aesthetic coating layer.

Another example of a lightweight block 300 includes an insulatingconcrete form (ICF) as the block substrate (see FIG. 5, 6A-6B), whichcan modified to include a an aesthetic coating layer 314 similar toaesthetic coating layer 114 on a side of lightweight block 100 ofFIG. 1. Accordingly, a similar process can be used to form the aestheticcoating layer 114 on a surface of lightweight block 300.

Lightweight block 300 can be stackable such that multiple lightweightblocks 300 can be stacked in a number of configurations in order to forma wall 301. For example, the lightweight blocks can be straight blocks(see FIGS. 5-6B), corner blocks (not shown), T blocks (not shown),curved blocks (not shown), angled blocks (not shown), and the like.

Lightweight blocks 300 can be modular and have interlocking features,providing for stabilization of the blocks during assembly to form a wallform. For example, in one embodiment, a top surface 306 a of a firstlightweight block 300 can include a series of alternating depressions307 and protuberances 308 which can mate with corresponding depressionsand protuberances on a bottom surface 306 b of a second lightweightblock 300 when the second lightweight block 300 is placed on top of thefirst lightweight block 300.

As shown in FIG. 6B, the bottom edge 306 b and top edge 306 a of a side304 can have inverse interlocking features. In FIG. 6B for example, alightweight block 300 includes a first side 304 a and a second side 304b, which are joined by a series of supports 310. A top surface 306 a ofthe first side 304 a has a depression 307, and an opposing bottomsurface 306 b of the same side has a protuberance 308. As discussedabove, the alternating series of protuberances 308 and depressions 307along the top surface 306 a and bottom surface 306 b can be positionedalong the length of the lightweight block 300.

The second side 304 b can have an alternating series of depressions 307and protuberances 308, though the alternating pattern of the top surface306 a and bottom surface 306 b of the second side 304 b, can be“opposite” of the first side 304 a. For example, in the cross-sectionalview shown in FIG. 6B, the top surface 306 a of the first side 304 a hasa depression 307, while the top surface 306 a of the second side 304 bhas a protuberance 308. This opposite or staggered patterning of thefirst side 304 a relative to the second side 304 b allows for thelightweight blocks 300 to be modular forms that can be assembled (e.g.,stacked) in a staggered manner (see e.g., FIGS. 5, 11A-11B) to avoidlong vertical seams, which can weaken the final structure.

The lightweight blocks 300 can further include a series of supports 310,which include one or more fastening ends 313 integrally formed withinthe block substrate of sides 304 a, 304 b. In some embodiments (seee.g., FIGS. 13A and 13B), only one side 404 is molded onto or integrallyformed with the support 410, such as for example, when the modular blockcomprises one side 404 comprising a polymer substrate material and atemporary form 409 (e.g., wood).

As illustrated in FIGS. 6A and 6B, supports 310 can have a number ofprongs 312 configured to receive reinforcement bars 311 (“rebar”). Oncea first row 315 (see FIG. 5) of modular lightweight blocks 300 arearranged end-to-end, rebar 311 can be positioned within the prongs 312.A second row of modular lightweight blocks 300 can then be arranged ontop of the first row 315. Once the rows of modular lightweight blocks300 have been stacked to a desired height, a pump hose 303 can be usedto pump a filler substrate 305 such as, for example, concrete, interiorbonding concrete, grout, mortar, or the like, into the space between thesides 304 a, 304 b of the modular lightweight blocks 300.

One or more sides 304 of the lightweight modular block substrate canhave a textured exterior 316 to promote the bonding of an aestheticcoating (e.g. plaster or stucco composition 314) to a side 304 of thelightweight block 300. The one or more sides 304 (304 a, 304 b) can beformed of a low-density substrate. The low-density substrate maycomprise lightweight foam concrete, lightweight foam ceramic, expandedpolystyrene (EPS), extruded polystyrene foam (XPS), polyurethane foam,cement-bonded wood fiber, cement-bonded polystyrene beads, cellularconcrete, or similar materials.

As explained in greater detail below, the plaster, stucco, or otheraesthetic coating composition is formulated to provide an aestheticappearance resembling that of natural or cut stone. The base blockmaterials (i.e., block substrates) and the manufacturing methods used toform the lightweight blocks provide a less expensive and/or lower weightalternative to natural or cut stone. Further, using natural or cut stonemay involve difficulties in finding a proper supply of stone. In otherwords, the use of natural stone may require an extensive search for aproper supply that meets size and/or composition and/or aestheticrequirements. On the other hand, the lightweight block productsdescribed herein are capable of controlled manufacture according toparticular project requirements and can have an almost endless varietyof colors and/or textures resembling stone or having a desired look.

Because the lightweight blocks are made using a lightweight blocksubstrate, they will typically have a weight that is significantly lessthan a similarly size piece of natural or cut stone. Lightweight blockscan therefore provide aesthetic benefits of natural or cut stone whilereducing limitations associated with cost, weight, and/or supply ofstone.

II. Aesthetic Coating Compositions

The plaster, stucco, or other aesthetic coating composition may beformulated to include: 1) a binder component, 2) an aggregate component,preferably including at least two types and/or gradations of aggregate(e.g., limestone and/or silica aggregates of different sizes), andoptionally 3) an adhesive component. The aesthetic coating compositionmay be applied to a block substrate to form a decorative aestheticcoating layer, such as shown in FIG. 1.

The binder component preferably includes a cementitious binder, such aswhite Portland cement. Although some embodiments may include ordinary(grey) Portland cement, the cementitious binder component is preferably50% or more, 60% or more, 75% or more, or 90% or more, or 95% or more,or about 100% white Portland cement. A supplementary cementitiousmaterial may optionally be included, examples of which include fly ash,ground granulated blast furnace slag (GGBFS), metakaolin, silica fume,pumice, ground glass, and natural pozzolan. The cementitious bindercomponent may make up about 15% to 45%, or more preferably about 20% to40% (e.g., about 25% to 35%) of the weight of the plaster composition(excluding water).

Examples of other cementitious binders include calcium aluminate cement(CAC), magnesium oxychloride cement, CSA cement (calcium sulphatealuminate cement), phosphate cement, silicate cement, geopolymer cement,and alkali-activated slags and pozzolans.

Alternatively, or in addition to the cementitious binder, the bindercomponent may comprise a polymer binder, such as an acrylic binder thatincludes an acrylic resin and/or polymer. Other polymer binders include,but are not limited to, polyvinyl alcohol (PVA), alkyd resins,polyurethane, and other materials typically used to paint, seal orprotect a wall surface.

The aggregate component may constitute about 55% to 85%, or morepreferably about 60% to 80% (e.g., about 65% to 75%) of the weight ofthe aesthetic coating composition (excluding water). The aggregatecomponent preferably includes at least two gradations. Beneficialresults closely resembling the appearance of natural or cut stone havebeen shown when both a fine sand and a coarse sand are included in theaggregate component of the aesthetic coating composition.

The aggregate may include one or more gradations of limestone, one ormore gradations of silica, or a combination thereof. Limestone is softerthan silica and can be easier to sand. Silica may provide a more definedcrystal structure and greater strength. An aggregate may include, forexample, a fine limestone portion, and a coarse limestone and/or silicaportion. Alternatively, nn aggregate may include a fine silica portion,and a coarse limestone and/or silica portion.

As used herein, the “fine” or “fine sand” portion of the aggregate is asand having a D90 of about 0.425 mm or less (i.e., 90% or more of thematerial passes through a 40 mesh sieve), or about 0.300 mm or less(i.e., 90% or more of the material passes through a 50 mesh sieve) oreven about 0.212 mm or less (i.e., 90% or more of the material passesthrough a 70 mesh sieve). For example, the D90 of the fine sand portioncan be within a range of about 0.075 mm to 0.425 mm, or about 0.105 mmto 0.300 mm, or about 0.150 mm to 0.212 mm. The fine sand portion canalso have a D50 that is about 0.075 mm or less (i.e., 50% or more of thematerial passes through a 200 mesh sieve). The fine sand can beconsidered to be a filler rather than an SCM.

As used herein, the “coarse” or “coarse sand” portion of the aggregateis a sand or other particle having a D90 of greater than about 0.425 mm(i.e., less than 90% of material passes through a 40 mesh sieve), orgreater than about 0.60 mm (i.e., less than 90% of material passesthrough a 30 mesh sieve). For example, the D90 of the coarse sandportion may be within a range of about 0.425 mm to 2.80 mm, or about0.60 mm to 1.70 mm. The coarse sand portion may have a D50 within arange of about 0.212 mm to 0.60 mm, or about 0.300 mm to 0.425 mm. Inaddition, the coarse sand portion may have a D10 within a range of about0.075 mm to 0.212 mm, or about 0.105 mm to 0.150 mm.

Plaster, stucco, or other aesthetic coating compositions havingaggregates with such fine and coarse sand portions have been found toeffectively provide the appearance of natural or cut stone. The finesand portion enables effective application of the aesthetic coatingcomposition to the treated surface and facilitates even coverage of thetreated surface. At the same time, the coarse sand portion providesvisible crystal facets that can be exposed following finish work (e.g.,sanding, polishing, sandblasting, acid etching, acid finishing, orexposed sand grain finishing using a face retarder and power washer) ofthe treated surface. These visible crystals resemble the appearance ofcrystals within natural or cut stone.

Adjusting the ratio of the fine aggregate portion to the coarseaggregate portion can enhance the resemblance to natural or cut stone.For example, the appearance of the aesthetically coated surface wasfound to resemble natural or cut stone when the ratio of the fineaggregate portion to the coarse aggregate portion is about 1:9 to about5:5, or more preferably about 2:8 to about 4:6. For example, the fineaggregate portion may make up about 10% to about 50%, or about 20% toabout 45%, or about 25% to about 40% of the weight of the aggregatecomponent of the aesthetic coating composition, and the remainder may bemade up of the coarse aggregate portion. These ratios were found tobeneficially balance the different features of the fine and coarseaggregate portions to result in an aesthetic coating composition havinggood workability, finishability, and resemblance to natural or cutstone.

In some embodiments, the plaster, stucco, or other aesthetic coatingcomposition may further include an adhesive component that promotesadhesion to the lightweight block substrate. The aesthetic coatingcomposition may include an adhesive component in an amount ranging fromabout 2% to 10%, or about 3% to 9%, or about 4% to 8% of the weight ofthe composition (excluding water). In a preferred embodiment, theadhesive component is a latex or latex-based adhesive (e.g., polyvinylacetate, polyvinyl alcohol, and the like), although other embodimentsmay additionally or alternatively utilize other adhesives such as thosebased on styrene, acrylonitrile, natural rubber, neoprene, polyurethane,and combinations thereof.

Inclusion of an adhesive component has been found to enhance theinternal integrity of the aesthetic coating composition after it cureson the treated substrate surface. Additionally, the adhesive componentaids in maintaining a strong bond interface between the aestheticcoating composition and the treated substrate surface so that effectivecoverage and bonding can occur. It can also minimize sloughing,buckling, or other undesirable artifacts from occurring duringapplication of the aesthetic coating composition, which thereby reducesthe occurrence of these artifacts in the finished, cured aestheticcoating layer.

One or more additional components may also be included in the aestheticcoating composition to aid in application and/or to provide desiredproperties to the finished, cured aesthetic coating layer. For example,one or more dyes or colorants (e.g., white, cream, tan, brown, orange,red, and the like) may be included to provide a desired color scheme tothe aesthetic coating and further aid in reproducing the appearance ofnatural or cut stone. A set retarder used to slow down cement hydrationcan be included to extend working time of a cementitious plaster orstucco. In addition, or alternatively, a set accelerator may beincluded. Water reducers and/or other admixtures known in the art can beincluded. Reinforcing fibers, such as polymer or glass fibers known inthe art can be used.

III. System and Method for Manufacture of Modular Blocks

FIGS. 2 and 3 are a side view and a top view, respectively, of anexemplary embodiment of a manufacturing system and related process formanufacturing lightweight blocks similar to lightweight block 100 ofFIG. 1. As illustrated, a series of lightweight block substrates 200 areconveyed toward a series of modifying machines. The block substrates 200may be conveyed using a conveyor belt, a roller conveyor, slideconveyor, or other suitable mechanism for moving the block substrates200 relative to a series of modifying machines. Additionally, oralternatively, the modifying machines may be configured to move relativeto the series of block substrates 200, though typically it will be morestraightforward to convey the block substrate 200 relative to stationarymachinery. In addition, although the machinery is oriented in theillustrated embodiment to apply an aesthetic coating composition to anupper surface of the block substrate 200, it will be understood that thesame mechanisms may be oriented on a side or bottom surface of the blocksubstrate 200.

In a first step, the block substrate 200 first passes an applicator 226,which applies an amount of the aesthetic coating composition 224 to asurface of the block substrate 200 to form an intermediate block 202having an intermediate aesthetic coating layer 214. The applicator 226may be formed as a chute, for example. Following application of theaesthetic coating composition, the block substrate 200 is moved towardand past a leveler 228. The leveler 228 may be a blade, bar, edge,roller, or other such structure capable of spreading and/or removingexcess plaster from the treated surface of the block substrate 200. Theleveler 228 is positioned with a predetermined gap between the treatmentsurface and the lower extent of the leveler 228. Excess aestheticcoating composition removed by the leveler 228 may be collected in acollection bin 229.

The thickness of the aesthetic coating layer 214 may be set according todesign preferences or particular application needs. Typically, effectiveresults are seen with an aesthetic coating layer thickness of about ⅛inch to ⅜ inch, such as ¼ inch, although thicknesses greater than ⅜ inchor less than ⅛ inch are certainly within the scope of the disclosure.The leveler 228 or other apparatus (not shown) may provide a depressionor void on one or more sides of the coated block surface to permitreceipt and application of grout to provide aesthetic grout or mortarlines, thereby completing the natural look of cut stone pieces.

Following the leveling step, the intermediate block 202 may be conveyedto a holding area to allow the aesthetic coating layer 214 to harden orcure. The curing time can be for about 12 hours to about 7 days, butusually that passage of about 24 hours provides sufficient hardening sothat the lightweight blocks can be handled (although cementitiouscompositions may continue building strength for weeks or months,especially when exposed to moisture).

FIG. 4 illustrates additional processing steps that may be carried outon the intermediate block 202 following hardening or curing of theaesthetic coating layer 214. As shown, the intermediate block 202 may beconveyed to one or more finishers 230. The finisher(s) may be one ormore sanders (e.g., belt sanders or orbital sanders), grinders,polishing devices, such as a lapping device with a suitable abrasive,sandblasters, applicators for acid etch, acid wash, and/or faceretarder, and power washers, for example. The (x n) illustrated in FIG.4 represents the fact that additional finishers may be included. Forexample, the intermediate block 202 may first pass through a coarsegrade sander followed by one or more progressively finer grade sandersor polishers.

As described above, the beneficial formulation of the aesthetic coatingcomposition 224, in combination with the finishing process, enables thefinished surface of the aesthetic coating layer 214 to resemble naturalor cut stone. In particular, after passing through the one or morefinishers 230, the finished surface of the aesthetic coating layer 214can include visible crystal facets of appropriate size distributedacross the finished surface in a manner that resembles natural or cutstone.

Following finishing of the aesthetic coating surface, the intermediateblock 202 may be moved past a cleaner 232. The cleaner 232 may beconfigured to discharge compressed air, and/or water, and/or othersuitable fluid to clean the surface of the aesthetic coating layer 214.Other embodiments may additionally or alternatively utilize one or morebrushes or vacuum devices to remove residual dust/debris from thefinished surface.

The intermediate block 202 may then be conveyed to a sealer system 234configured to apply a polymer or other sealer to the finished surface ofaesthetic coating layer 214. The sealer system 234 may utilize a sprayerand/or roller brush, for example, to apply the sealant to the finishedsurface of the aesthetic coating layer 214. Examples of sealers includeany sealer suitable for use in sealing concrete, including silanes,siloxanes, siliconates, epoxies, urethanes, acrylic polymers andcopolymers, alkali silicates, and integrated sealers.

The method of manufacture described above can be applied to themanufacturing of other lightweight blocks, such as insulated concreteform (ICF) 300 of FIGS. 5-12B, and insulated concrete form (ICF) 400 ofFIGS. 13A-14. The insulated concrete forms 300, 400 of FIGS. 5-14comprise at least one side 304, 404, which can comprise a low-densitysubstrate, as discussed above.

In a first step, as illustrated in FIG. 7, the first side 304 a of thelightweight block substrate 300 passes an applicator 326, which appliesan amount of the plaster, stucco, or other aesthetic coating composition324 to a surface of the first side 304 a to form an intermediate block302 having an intermediate aesthetic coating layer 314. The applicator326 may be formed as a chute.

Following application of the aesthetic coating composition 324, thefirst side 304 a of the intermediate block 302 is moved toward and pasta leveler 328. The leveler 328 may be a blade, bar, edge, roller, orother such structure capable of spreading and/or removing excessaesthetic coating composition 324 from the treated surface first side304 a. The leveler 328 is positioned with a predetermined gap betweenthe treatment surface and the lower extent of the leveler 328. Excessaesthetic coating composition that is removed by the leveler 328 may becollected in a collection bin 329 (FIG. 8).

The thickness of the aesthetic coating layer 314 may be set according todesign preferences or particular application needs. Typically, effectiveresults are seen with a plaster layer thickness of about ⅛ inch to ¾inch, such as ¼ inch, ⅜ inch, ½ inch, or ⅝ inch, although thicknessesgreater than ¾ inch or less than ⅛ inch are certainly within the scopeof the disclosure. The leveler 328 or other apparatus (not shown) mayprovide a depression or void on one or more sides or regions of thecoated block surface to permit receipt and application of grout toprovide aesthetic grout or mortar lines, thereby completing the naturallook of cut stone pieces.

Following the leveling step, the intermediate block 302 may then beconveyed to a holding area to allow the aesthetic coating layer 314 toharden or cure. The curing time period can be for about 12 hours to 7days, but usually about 24 hours provides sufficient hardening beforethe coated blocks can be handled (although cementitious compositions maycontinue building strength for weeks or months, especially when exposedto moisture).

FIG. 9 illustrates additional processing steps that may be carried outon the intermediate block 302 following hardening or curing of theaesthetic coating layer 314. As shown, the intermediate block 302 may beconveyed to one or more finishers 330. The finisher(s) may be sanders(e.g., belt sanders or orbital sanders), grinders, polishing devices,such as a lapping device with a suitable abrasive, sandblasters,applicators for acid etch, acid wash, and/or face retarder, and powerwashers, for example. The (x n) illustrated in FIG. 9 represents thefact that additional finishers may be included. For example, theintermediate block 302 may first pass through a coarse grade sanderfollowed by one or more progressively finer grade sanders or polishers.

As described above, the beneficial formulation of the aesthetic coatingcomposition 324, in combination with the finishing process, enables thefinished surface of the aesthetic coating layer 314 to resemble naturalor cut stone. In particular, after passing through the one or morefinishers 330, the finished surface of the aesthetic coating layer 314can include visible crystal facets of appropriate size distributedacross the treated surface in a manner that resembles normal or cutstone.

Following the finishing of the aesthetic coating surface, theintermediate block 302 may be moved past a cleaner 332. The cleaner 332may be configured to discharge compressed air, and/or water, and/orother suitable fluid to clean the surface of the aesthetic coating layer314. Other embodiments may additionally or alternatively utilize one ormore brushes or vacuum devices, for example, to remove residualdust/debris from the finished surface.

The intermediate block 302 may then be conveyed to a sealer system 334configured to apply a sealant (e.g., integrated sealer) to the finishedsurface of aesthetic coating layer 314. The sealer 334 may utilize asprayer and/or roller brush, for example, to apply the sealant to thefinished surface of the aesthetic coating layer 314.

In some embodiments, the method of manufacture can be applied to asecond side 304 b of an intermediate block 302, as shown in FIGS. 10-11.Applying an aesthetic coating on both sides of a lightweight block maybe preferred when an aesthetic look, such as natural or cut stone, ispreferred on both sides of a wall, such as on outdoor retaining walls,garden walls, courtyard walls, or the like. Similar aesthetic finishesmay be desired by individuals wishing to have the appearance of naturalor cut stone, or other finishes on the interior of finished structures.

FIGS. 12A and 12B illustrate a method of assembling the finishedlightweight blocks 300 (also, applicable to modular block 400), whereinthe blocks 300 are stacked in a staggered manner, which enhances thestructural integrity of the resulting wall. A layer of mortar or grout340 can be applied to the top surface 306 of a first block 300 beforeplacing another block 300 on top of the first block 300. The grout 340can then be smoothed to enhance the appearance of the aesthetic coatingcomposition 314 by imparting the appearance of natural or cut stone laidin a traditional manner (i.e. brick and mortar). Aesthetic coatingcomposition 314 can be the same as or similar to the aesthetic coatingcomposition 114.

Turning now to FIGS. 13A and 13B, which illustrate another embodiment ofa lightweight modular block 400. The lightweight block 400, as shown,comprises a first side and a second side, where the first side cancomprise a side form 404 made of a lightweight material, such asexpanded polystyrene, and the second side can comprise a temporary form409, such as a wooden board. The side form 404 will typically bemodified to include an aesthetic coating layer on an exposed surface.The side form 404 can include a series of supports 410 embedded orintegrally formed with the side form 404, and the free end 416 of eachof the supports of the series of supports 410 can have a receivingfeature 418 providing for the connection of a temporary form 409 to theseries of supports 410. Fasteners 417 configured to selectively connectto the receiving feature 418 can be used to connect the temporary form409 to the series of supports 410. The temporary form 409 can comprisewood, or like materials which can be easily removed from cured concreteto yield an exposed concrete surface.

FIG. 14 illustrates an example of a wall 415 comprising lightweightmodular blocks 400. Similar to lightweight modular block 300,lightweight modular block 400 comprises a top surface 406 a and a bottomsurface 406 b, which each include a series of alternating depressions407 and protrusions 408 to facilitate secure stacking of blocks 400.After lightweight modular blocks 400 are stacked in a staggeredconfiguration to form a wall 415, a pump hose 403 can be used to pumpconcrete 405 to fill the space between the temporary form 409 and theside form 404. Once the concrete 405 has cured, the temporary forms 409are removed to reveal a concrete surface. Lightweight modular block 400may be preferred in structures where the wall does not need to befinished on both sides, such as in a parking structure or elevatorshaft.

Lightweight modular blocks 100, 300, 400 that are pre-finished with anaesthetic coating layer 114, 314 and manufactured according to themethods described above, can be advantageous for construction. Forexample, lightweight modular blocks 100 need only be stacked to providea decorative aesthetic finish and may not require further finishing,except for addition of optional grout or mortar lines. Furthermore,ICFs, which form the block substrate for modular blocks 300, 400, can beshipped flat, thereby significantly reducing shipping costs due toreduced size and weight of materials, and because the lightweightmodular blocks 300, 400 are pre-finished, additional purchase orshipment of heavy finishing materials, such as cut stone or brick is notnecessary.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. A method of manufacturing a lightweight block adapted to give theappearance of natural or cut stone, comprising: providing a lightweightblock substrate having a density of less than 1680 kg/m³; and applyingan aesthetic coating composition to at least one surface of thelightweight block substrate to form an aesthetic coating layer, theaesthetic coating layer being formulated to resemble natural or cutstone when applied to the surface of the block and allowed to harden. 2.The method of claim 1, further comprising leveling the aesthetic coatinglayer after applying the aesthetic coating composition.
 3. The method ofclaim 1, further comprising allowing the aesthetic coating layer tocure, and following curing, finishing an outer surface of the aestheticcoating layer using one or more finishers.
 4. The method of claim 3,wherein the one or more finishers comprise one or more of a sander,polisher, sandblaster, applicator for acid etch, applicator for acidwash, applicator for face retarder, or power washer.
 5. The method ofclaim 4, wherein finishing comprises successively sanding and/orpolishing the outer surface of the aesthetic coating layer withprogressively finer sanders and/or polishers.
 6. The method of claim 1,further comprising applying a sealer to the aesthetic coating layer. 7.The method of claim 1, the aesthetic coating composition comprising: abinder component selected from a cementitious binder selected fromPortland cement, white cement, and supplementary cementitious material(SCM) and a polymer binder selected from an acrylic binder, polyvinylalcohol binder, alkyd resin binder, and polyurethane binder; and alimestone and/or silica aggregate component including at least twogradations of aggregate.
 8. The method of claim 7, wherein white cementconstitutes about 50% or more, 60% or more, 75% or more, or 90% or more,or 95% or more, or about 100%, of the cementitious binder.
 9. The methodof claim 7, wherein the cementitious binder constitutes about 15% to45%, or about 20% to 40%, or about 25% to 35%, of the dry weight of theaesthetic coating composition.
 10. The method of claim 9, wherein theaggregate component constitutes about 55% to 85%, or about 60% to 80%,or about 65% to 75%, of the dry weight of the aesthetic coatingcomposition.
 11. The method of claim 7, wherein the aggregate componentcomprises a fine sand portion and a coarse sand portion, wherein thefine sand portion has a D90 within a range of about 0.075 mm to 0.425mm, or about 0.105 mm to 0.300 mm, or about 0.150 mm to 0.212 mm and/orwherein the fine sand portion has a D50 that is 0.075 mm or less, andwherein the coarse sand portion has a D90 within a range of about 0.425mm to 2.80 mm, or about 0.60 mm to 1.70 mm and/or wherein the coarsesand portion has a D50 within a range of about 0.212 mm to 0.60 mm, orabout 0.300 mm to 0.425 mm and/or wherein the coarse sand portion has aD10 within a range of about 0.075 mm to 0.212 mm, or about 0.105 mm to0.150 mm.
 12. The method of claim 7, wherein the aesthetic coatingcomposition further comprises a latex adhesive component in an amountranging from about 2% to 10%, or about 3% to 9%, or about 4% to 8%, ofthe dry weight of the aesthetic coating composition.
 13. The method ofclaim 1, wherein the lightweight block substrate comprises an insulatedconcrete form (ICF), which includes: a first side; a second side; and aplurality of supports, connecting the first side to the second side,wherein each support comprises a first fastening end and a secondfastening end, the first fastening end being embedded within the firstside, wherein at least the first side comprises a low-density substratematerial having a density less than 1000 kg/m³.
 14. The method of claim13, wherein the low-density substrate has a density of less than about750 kg/m³, less than about 500 kg/m³, less than about 300 kg/m³, lessthan about 200 kg/m³, less than about 150 kg/m³, less than about 100kg/m³, less than about 80 kg/m³, or less than about 60 kg/m³.
 15. Themethod of claim 13, wherein the first and second sides each comprise alow-density polymer foam.
 16. The method of claim 13, wherein the firstside comprises a low-density polymer foam and the second side comprisesa removable form.
 17. A lightweight block adapted to give the appearanceof natural or cut stone, comprising: a lightweight block substrateformed from a lightweight material having a density less than 1680kg/m³; and an aesthetic coating composition on at least one surface ofthe lightweight block substrate to form an aesthetic coating layer, theaesthetic coating layer being formulated to resemble natural or cutstone.
 18. The lightweight block of claim 17, wherein the lightweightmaterial has a density of less than about 750 kg/m³, less than about 500kg/m³, less than about 300 kg/m³, less than about 200 kg/m³, less thanabout 150 kg/m³, less than about 100 kg/m³, less than about 80 kg/m³, orless than about 60 kg/m³.
 19. The lightweight block of claim 17, whereinthe lightweight block substrate is an insulated concrete form (ICF),which includes: a first side; a second side; and a plurality ofsupports, connecting the first side to the second side, wherein eachsupport comprises a first fastening end and a second fastening end, thefirst fastening end being embedded within the first side, wherein atleast the first side comprises a low-density substrate material having adensity less than about 150 kg/m³.
 20. A structural wall comprising aplurality of lightweight blocks of claim 17 arranged in a staggered andlayered configuration and concrete positioned within one or moreinterior spaces provided by the lightweight blocks.